by Francesca Di Cecio
Anyone who has ever sung in a church or cathedral choir knows the difficulty of performing in the unaccommodating acoustics associated with those buildings. One notorious for that trait is St Paul’s Cathedral. As you belt out your Mendelssohn hymn, that carefully rehearsed “lift thine eyes” flies up into the incredibly high domed ceiling for the angels (real and mosaic) to hear. Crucially, a result of that is that you as a singer can barely hear yourself or those around you. It is not easy to sing confidently when it feels like you are the only one there, let alone coordinate timings and dynamics sensitively with other performers.
This challenge, faced by choristers the world over, is one all professional musicians also have to deal with on a regular basis. Adjusting to the acoustics of a performance space is a vital task requiring intensive listening during pre-concert rehearsals, often from multiple different vantage points around the room. But a well-designed concert venue should not be a hindrance for its occupant musicians. Architects for these buildings have several layers of considerations to make, including how clearly audience members can hear music from the stage all around the hall, how clearly performers can hear themselves and each other – even how faithful the sound the audience hears is with respect to the sound the performers hear. On top of that, they need to take care for the finer details within those factors, such as the uniformity of registers (does the bass register completely disappear while higher pitches cut through too harshly?).
That might sound complicated enough, but acousticians have another obstacle still to contend with – the human brain. According to experts, our brains erase the reflected sounds that come closely after an initial sound, listening only to the primary sound wave and the more delayed ones, which we hear as echoes. But it’s the reflected waves that carry better – the initial sound is often not enough to fill the hall right to the back rows.
Using first lasers and then sounds across the entire audible range of frequencies, acousticians map the paths of sound waves across the room, strategically placing reflectors around the venue in an attempt to find that perfect balance of direct sound waves for clarity and reflected sound waves for sonic power.
These reflectors are clearly visible in many of the world’s most renowned concert halls, such as the Sydney Opera House, the Berlin Philarmonie, and the Royal Albert Hall, where sleekly sculpted panel-like structures dangle from the ceiling and form an integral part of the venue’s aesthetic, as well as its sound quality, of course. The beauty of these advances in acoustics is that they allow us to enjoy live music from all sorts of genres and backgrounds – cutting-edge compositions completed last month, multimedia pieces, Renaissance music played on period instruments – all using modern acoustical innovations to ensure the best possible quality of sound reaches our ears.